Description Title of Invention ANTENNA DRVTCE Technical Field [00011 The present disclosure relates to an antenna device suitable to receive a broadcast signal in a moving object, such as a vehicle, Background Art [00021 Conventionally, as an antenna for a car navigation device installed hi a vclucle and a PND (Personal Navigation Device) attached to a vehicle, a rod antenna 15 attached oulside a vehicle or a film antenna that can be bonded to the windshield or the rear glass is used frequently. [00031 In the case where a moving object, such as a vehicle, receives a broadcast, due to the influence of fading, Ihe signal level of the received signal varies 20 considerably, and therefore, diversity reception is performed frequently for the purpose of making up the deterioration in the received signal due to the influence of fading. However, in order to perform diversity reception, it is necessary to provide a plurality of antennas. [00041 2G Because of this, as an antenna for performing diversity reception, the film antenna that liardly affects the external appearance is selected more frequently than the rod antenna that mars the external appearance because the nnmbcr of antennas increases. [0005] 30 Tor example, In Patent Literature 1, Ihe technique to enable stable reception of the bmadeasl wave by installing a film antenna on four surfaces, i.e. the front, rear, SP342942WO00 2/28 left, and right surfaces of a vehicle, Citation Ust Patent Literature 5 [0Q06J Patent Literature 1: JPH11-017595A Summary of Invention Tcclmical Problem 10 [0007] However, it is difficult to attach a film antenna to a window, and therefore, it is necessary for a user to ask an expert to perform attachment in order to bond the film antenna to an appropriate position in a favorable manner. Tn such a case, a user needs to pay for the work for attachment, besides the expense for the film antenna. 15 10008] Further, because the film antenna uses a member whose electric conductivity is not so good as an antenna element and the length or the antenna cable Is long, the gain of the antenna is low compared to that or the rod antenna etc. In order to solve this problem, an amplifier is also used in many film antennas. 20 However if the amplifier is provided, there arise such problems that power consumption increases and that a dedicated connector is necessary, [0009] An object of the present disclosure is to provide an antenna device excellent in recqriion performance and easy to attach. 25 Solution to Problem [0010] The antenna device or the present disclosure includes an antenna element configured to receive a broadcast wave and a signal that is superimposed on the ,10 broadcast wave and then is transmitted, and a ground element having a predetermined length and configured so that the relative angle with respect to the SI'342942 WOOO 3/28 antenna clement can be adjusted. Further, there is provided a feeding part to which the antenna element and the ground antenna are connected and from which a signal received hy the antenna element is taken out [0011]' 5 With this configuration, capacitivc coupling occurs between the ground element and a mclal portion of the vehicle body mounting an onboard antenna by adjusting the angle of the ground element with respect to the antenna element. Consequently, the area of the portion that functions as the ground of the antenna device for receiving a broadcast signal increases, and therefore, the reception 10 characteristics of the antenna device improve. Further, the antenna device is formed only by arranging the antenna element and the ground element on, for example, the dashboard etc. of the vehicle body, and therefore, it is possible to extremely easily attach the antenna device, 1G Advantageous Eflects of Invention [00121 According to the present disclosure, there is provided an antenna device excellent in reception performance and easy to attach. 20 Brief Description of Drawings [0013] [FIG. 1J FIG 1 is an explanatory diagram illustrating a configuration example of an onboard antenna according to a first embodiment of the present disclosure. [F1Q 2] FIGS. 2A to 2C are a graph and tables showing the frequency-gain 25 chaj-atterislics in the UHF baud of the onboard antenna according to the first embodiment of the present disclosure, in which FIG. 2A is a graph, FIG, 2B is a (able showing the gain characteristics when vertically polarized waves arc received, and FIG 2C is a table showing the gam characteristics when vertically polarized waves are received. 30 [FIG. 3] FIG. 3 is an explanatory diagram illustrating an arrangement example of the onboard antenna according to the first embodiment of the present disclosure. SP3+2W42WOOO Am [FIG 4] FIGS. 4A and 4B are graphs showing the reception characteristics of the onboard antenna accoi-ding lo (he first embodiment or the present disclosure, in which FIG 4A is a graph showing the C/N ratio in the signal received by a conventional film antenna and FIG, 4B is a graph showing the C/N ratio in the signal !i received by the onboard antenna of the present disclosure. [hIG 5J FIG 5 is an explanatory diagram illustrating a configuration example or an onboard antenna according to a modified example 1 of the first embodiment of the present disclosure. [FIG 61 FIGS. 6A to 6C are a graph and tables showing the frequency-gain 10 characteristics in the UUP band of the onboard antenna according to the modified example 1 of the first embodiment of the present disclosure, in which FIG. 6A is a graph, FIG GU is a (able showing the gain characteristics when vertically polarized waves are received, and FIG. 6C is a tabic showing the gain characteristics when vertically polarized waves are received. 1G [F\G. 7] FIG 7 is an explanatory diagram illustrating a configuration example of an onboard antenna actxirding to a modified example 2 of the first embodiment of the present disclosure. [FIG. S] FIGS. 8A to 8C are a graph and tables showing the frequency-gain characteristics in the U1JH band of the onboard antenna according to the modified 20 example 2 of the first embodiment of the present disclosure, in which FIQ 8A is a graph, FIG. 8H is a (able showing the gain characteristics when vertically polarized waves are received, and FIG 8C is a (able showing the gain characteristics when vertically polarized waves are received. [KIG 9] FIG 9 is an explanatory diagram illustrating a configuration example of an 25 onboard antenna accusing Lo a modified example 3 of the first embodiment of the present disclosure. [FIG. 10] FIG 10 is an explanatory diagram illustrating a configuration example of an onboard antenna acconling to a second embodiment of the present disclosure. fRG 11] FIG 11 is an explanatory diagram illustrating a configui'aticm example of 30 an onboard antenna according to a modified example of the second embodiment of the present disclosure. SP 342942 WOOO 5/28 [I'lG 12] FIGS. 12A to 12C are a graph and tables showing the frequency-gain characteristics in the IJTTF band or the onboard antenna according to the modified example of the second embodiment of the present disclosure, in which FIG. 12A is a graph, FIG. I2B is a table showing the gain characteristics when vertically polarized 5 waves arc received, and I'lG, 12C is a lablo showing the gain characteristics when vertically polarized waves arc received. Description of Kmbodimenls TOO 14] 10 Hereinafter, preferred embodiments for embodying the present disclosure are described. Explanation is given In the order below, 1. First embodiment example (example in which an antenna element and a ground element arc connected via a suhslrale) 2. Modified example of first embodiment 15 2-1, Modified example 1 of first embodiment (example In which ait antenna element is configured by a substrate) 2-2. Modified example 2 of first embodiment (example in which an antenna clement is configured by a substrate and a J-type antemm is configured by a ground part different from a ground clement and the antenna elemenl) 20 2-3, Modified example 3 of first embodiment (example in which a plurality of anEcnna elements is provided and a connection part with a ground element is shared) 3. Second embodiment example (example in which a ground element is configured by a rod-shaped antenna) 25 3-1. Modified example of second embodiment (example in which a plurality of ground elements configured by a rod-shaped antenna is provided) 4. Various kinds of modified examples [0015] <1. First embodiment cxample> 30 FIG 1 is a schematic diagram illustrating a configuration example of an onboard antenna accoixfing to a first cmbodhnent of the present disclosure. An SP34294EWO00 6/23 onboard antenna I illustrated in FIG 1 includes an antenna element 10, a high frequency transmission line 20, a ground element 30, and a coaxial wire 40 as an antenna cable. In the present embodiment, the antenna element 10 is configured by a conductive wire material, such as a metal rod, and the antenna element 10 is G connected to a signal pattern (signal line) 21 of the high frequency transmission line 20 configured by a ground-attached coplanar line- The coplanar line is a transmission line in which the signal line and the ground conductor exist on the same plane. [0016] 10 As described above, in the high frequency transmission line 20, the groundattached coplanar line is used and on the surface of the substrate 21 configured by a plate-shaped dielectric, a signal pattern 22 and a ground conductor 23 are provided directly or via an insulating film. Between the signal pattern 22 and the ground conductor 23, a slit 24, which is a linear gap, is provided with an appropriate width. 15 The ground conductor 23 is formed also on the backside of-(he substrate 21 and is connected with the ground conductor 23 on the top surface normally via a through hole etc. and is configured so as to function as a ground. By configuring the high frequency transmission line 20 by a ground-attached coplanar line, the dielectric loss by the substrate is suppressed low, and therefore, it is possible to allow the high 20 frequency signal received by the antenna-clement 10 to pass without attenuation. [0017J To the ground conductor 23 on the substrate 21, the ground clement 30 configured by a conductive wire material, such as a metal rod, is connected. With this configuration, an antenna is configured by the antenna element 10 and the 25 ground element 30. By setting the total length of the length of the antenna element 10 and the length of the ground clement 30 to about V2 of the frequency desired to be received, it is made possible to receive the desired frequency by the onboard antenna 1. Actually, it is necessary to-appropriately adjust the elements according to the material of the antenna element 10, the material of flic ground element 30, and 3D . the reception frequency. Tn the present embodiment, for example, by setting the length of the antenna clement 10 to 13 cm and that of the ground clement 30 to 10 SI'342942 WO DO 7/28 cm, the antenna is configured to be able to receive frequencies in the IJHF band. , LOO 1K J To the end portion of the signal pattern 22 on the substrate 2lT on the opposite side of the side to which the antenna element 10 is connected, a core wins 6 41 of the coaxial wire 40 is connected and to the end portion of the ground conductor 23, an external conductor 43 of the coaxial wire 40 is connected. 1R other words, at the tip end portion of Ihe coaxial wire 40, a protective covering 44 and the external conductor 43 arc removed from (he coaxial wire 40 to bring about a state where a dielectric 42 and the core wire 41 are exposed. A feeding point Fp of the onboard 10 antenna 1 according to the present embodiment is a portion where the antenna element 10 protrudes in the leftward direction in FIG, 1 from the ground conductor 23. In other words, in Ihe portion where Ihe antenna element 10 and the signal pattern 22 arc connected, the feeding poinl Fp is formed. [ooiyj 15 A connection part 50, which is the portion where the antenna element 10, the ground element 30, and Ihe coaxial wire 40 are connected to the high frequency transmission line 20, is molded by a resin 51, such as etaslomer. In other words, the resin 51 is formed so as to cover the substrate 21, the signal patlcrn 22, and the ground conductor 23- To the end portion of the coaxial wire 40, on the opposite 20 side of the side connected to the connection part 50, a coaxial connector 45 is attached. [0020] Further, a ferritc core 60 as a high frequency attenuating member is provided on a part of the coaxial wire 40, By providing the feirite core 60, radio 25 waves are not induced on the external conductor 43 of the coaxial wire 40 from the fcrritc core 60 to the coaxial connector 45. Consequently, Ihe image cuiTent and noise received by the antenna clement 10 flow through the external conductor 43 from the connection part 50 to the feriite core 60. In other words, this portion functions as Ihe ground of (he antenna element 10. Consequently, it is possible to 30 prevent radio waves at ircquencics not intended from being induced wilh the external conductor 43 of the coaxial wire 40 functioning as an antenna. SP342942WO00 S/2S [0021J Further, because the portion that functions as the ground of the antenna extends, the reception characteristics of the antenna element 10 improve. It is assumed that the position on lhe coaxial wire 40 where lhe ferrile core 60 is provided fi (the distance from the connection part 50) can be adjusted to any position in accoidance with the frequency etc- desired to be received. In the present embodiment, by providing the ferrite tore 60 in the position 7 cm apart from the connection part 50, it is possible lo remove the noise and image current that are induced on the antenna element 10 most efficiently. 10 10022] Further, as described above, the feeding point Fp of the onboard antenna 1 is configured in (he position where the signal pattern 22 of the substiate 21 and the antenna clement 10 arc connected. By adjusting (he impedance of the feeding poinl Fp by the insertion position of the ferrite core 60 and the length of the antenna 15 element 10, it is made possible to determine the reception frequency. 100231 FIGS. 2A to 2C illustrate the frequency-gain characteristics when the onboard antenna 1 illustrated in FIG 1 receives a broadcast in the UHF band. As the coaxial wire 40 illustrated in FIG 1, one having a length of 3 m is used. FIG. 20 2A is a graph and FIG, 2B and FIG 2C illustrate data. The horizontal axis in FIG. 2A represents the frequency (MHz) and (he vertical axis represents the peak gain (dBd). The solid line in the graph represents the gain characteristics at lhe lime of reception of horizontally polarized waves and the broken line represents (he gain characteristics at the time of reception of vertically polarized waves. FIG 2D is £5 data indicative of the frequency-gain characteristics at the time of reception of vertically polarized waves and FIG 2C is data indicative of the frequency-gain characteristics at the time of reception of horizontally polarized waves. As illustrated in FIG 2A to FIG 2C, in the U11F band of 470 MHz to 870 MHz, it was confirmed lhat the gain characteristics of about -10 dB or more were obtained in the 30 horizontally polarized waves, i.e., the main polarized waves of a TV broadcast. [0024J SP342942WO00 9/2B FIGS- 3A and 3B illustrate Ihe. C/N ratio (Carrier to Noise Ratio) in Ihe received signal before demodulation by a comparison with that in the conventional film antenna. FIG. 3A is a graph showing the C/N ratio of the received signal in the ease where the onboard anlcnna 1 receives the signal in the UHF band {center 5 frequency is 475 MFlz) and FIG 3B is a graph showing the C/N ratio of the received signal in the case where the conventional film antenna receives the signal in the UHF band. As the conventional lifm antenna, one that uses an amplifier to increase the level of the received signal by 15 dB is used. In FIG. 3A and FIG 3B, the horizontal axis represents the frequency (MHz) and the vertical axis represents the 10 signal level (dBm). [0025] As illustrated in FIG 3A, in the signal received by the onboard antenna 1 according to the present embodiment, Ihe noise floor is a value in the vicinity of -122 dBm as represented by the broken line and the signal level is a value in the vicinity IS of-105 dBm as represented by the alternately long and shorl dash line. In contrast to this, in the signal received by (he conventional film antenna, Ihe level of Ihe signal is increased to the vicinity of -88 dBm as illustrated in FIG 3B. However, il is known lhal together with the signal level, (he noise floor is also increased to the vicinity of -108 dBm, In other words, in FIG. 3B, the C/N ratio indicated by the 20 interval between (he allemate long and short dash line representing the level of the noise floor and the broken line representing the signal level is not so much differenl from the C/N ratio in the onboard "antenna 1 illustrated in FIG 3A. At some frequencies, the C/N ratio in the onboard antenna 1 illustrated in FIG. 3A is somewhat better. 25 10-026J FIG 4 is a schematic diagram illustrating an arrangement example or the onboard antenna 1 to the vehicle body. In (he case where the onboard antenna 1 receives a broadcast using a high-order modulation system, for example, such as a fill I-segment broadcast, it is possible to improve the reception characteristics of the 30 antenna by providing the two onboard antennas 1 to perform diversity reception. FIG. 4 illustrates an example in which the two onboard antennas 1 are arranged at the SP342942WO00 10/28 right end and thclcitcnd, respectively, of a dashboard 102 in contact with the base of a windshield 101 of the vehicle. Tn the left and right onboard antennas 1, the antenna elements 10 are caused to extend straightforward so as to be parallel lo the base of the windshield 101 on the dashboard 102 and the ground elements 30 arc 5 caused lo extend along the left and right sides of the windshield 101. [0027J The coaxial connector 45 provided at the tip end portion of each of the coaxial wires 40 orthc left and right onboard antennas 1 is attached to a PND 200, Inside the PND 200, a receiver 210 is configured and the receiver 210 performs 10 diversity reception and demodulates a received signal. In the present embodiment, as the diversity reception, for example, the maximum ratio combining system of the spatial diversity is used. The signal demodulated by the receiver 210 is displayed on the screen of a display unit 220 including a liquid crystal display etc. r002fi] 16 By arranging the onboard antenna 1 in this manner, the metal body of the vehicle located at the end of the windshield 101 and the ground elemenl 30 of (he onboard antenna 1 arc capacitivcly coupled and the gnmnd or Ihc antenna is extended. Consequently, the level of the signal received by the onboard antenna 1 increases and iurther, the reception characteristics at the time of running also 20 improve. 10029] According to the onboard antenna 1 of the present embodiment, by the capacilive coupling of the ground element 30 and the metal portion of the vehicle body, the portion of the antenna that functions as the ground is extended, and 25 therefore, it is made possible lo obtain the reception characteristics equal to or more than those of the conventional film antenna. Purther, if is not necessary lo bond the antenna to tlic windshield 101 or the rear glass (not illuslratcd), and therefore, it is made possible to use a metal member having an excellent electric conductivity as the raw material of the anlenna clement 10. Purthermore, it is no longer necessary to 30 dispose the anlenna in the position apait from the car navigation device or the PND 200, such as the upper end of the windshield 101 and the rear glass, not illustrated, KP342G42WO00 11/28 and therefore, it is also possible to reduce the length of the antenna eable (the coaxial wire 40). [0030J Consequently, it is no longer necessary to provide an amplifier to make up 5 for the antenna gain that reduces resulting from the material of the antenna element and the cable length. Consequently, it is no longer necessary to use an expensive connector, such as Ihe MCX connector compatible with the amplifier, and therefore, it is possible to reduce the manufacturing cost. Besides thai, power consumption can be also suppressed. Further, Ihe onboard antenna 1 according to the present 10 embodiment only needs to be disposed on (he dashboard 102, and therefore, it is possible for a user to easily perform attachment by him/herself. Consequently, it is no longer necessary Tor a user to pay the attachment expense. [0031] Further, it is easy to increase the number of antennas, and therefore, it is 15 possible to peiforrn diversily reception. Consequently, it is made possible lo receive a full-segment broadcast, and therefore, it is made possihie lo clearly display character and videos of high precision even in the device whose screen size is comparatively large, such as the PND 200- Further, even in the case where the number of onboard antennas 1 is increased in order to perform diversity reception, 20 the onboard antenna 1 is not disposed on the surface of the windshield 101, and therefore, the visibility at the tunc of driving is no longer blocked. Furthermore, it is not necessary to attach the antenna outside the vehicle body, and therefore, the external appearance of the vehicle is no longer marred. [0032] 25 in the embodiment described above, the antenna element 10 and Ihe ground element 30 or ihe onboard antenna 1 are disposed on Ihe dashboard 102 of the vehicle, but they may be fixed by a clamper etc. [0033] Further, in Ihe embodiment described above, the antenna element 10 and the 30 ground element 30 are connected via the high frequency transmission line 20 configured by a ground-attached coplanar line, but this Js not limited. Another high SP342942WO00 12/28 ,frequency transmission line, such as a microstrip line, may be used. Alternatively, the antenna element 10 and the ground clement 30 may be connected directly to the coaxial wire 40 without using the high frequency transmission line 20- hi this case, the antenna clement 10 is connected to the core wire 41 of the coaxial wire 40 and 5 Ihc ground element 30 is connected to the external conductor 43 of Ihc coaxial wire 40. [00341 In the arrangement example illustrated in FIG 4, the example is given in which the two onboard antennas 1 are provided in order to perform diversity 10 reception, but another number of onboard antennas 1 may be provided, such as four, Application is available also m the case where diversity reception is not performed and in such a case, only one onboard antenna 1 is used. [0035] <2. Modified example of first embodiment examplc> 15 . Kext, a configuration example of an onboard antenna IA according to a modified example of the first embodiment described above is explained with reference to FIG 5 to FIG 9. [2-1. Modified example 1] FIG, 5 is a schematic diagram illustrating a configuration example of a 20 modified example 1. In FTG 5, the same symbols arc atlached to the portions coitesponding to those in FIG 1 and duplicated explanation is omitted. Tlic onboard antenna IA illustrated in FiCr, 5 differs from the onboard antenna I illustrated in FIG 1 in that an antenna element 10a is configured by a substrate made of a plate-shaped conductor. 25 [0036] Specifically, the width is set to the same width from the end to the end of the two ground conductors 23 (e,g,, 15 mm) and the length in the longitudinal direction is set to 115 mm, A substrate having no ground provided on the backside is connected with the end portion of the signal pattern 22 on the substrate 21. The end ,10 portion of the signal pattern 22 on the substrate 21 refers lo (he side to which the core wire 41 of the coaxial wire 40 or Ihc ground clement 30 is not connected. With this SP342942WO00 13/28 configuration, it is possible to increase the area of the antenna element 10a more than that of the onboard antenna 1 explained as Ihe fli-st embodiment. In Ihc present embodiment, the portion where Ihc antenna clement 10a and the substrate 21 are connected is covered by a resin case 51s. 5 [0037] FIGS. GA to 6C are a graph and lables showing Ihc frequency-gain characteristics when Ihe onboard antenna 1A of the present embodiment receives a broadcast in IheUHF band. The length of the coaxial wire 40 is set to 1,5 in, FIG 6A is a graph and FIG 611 and FIG GC illustrate data. The horizontal axis in FIG 10 6A represents the frequency (MHz) and the vertical axis represents Ihc peak gain (dlld). The solid line in the graph represents the gain characteristics at the time of reception of horizontally polarized waves and the broken line represents the.gain characteristics at the time of reception of vertically polarized waves, FIG (JB is data indicative of the frequency-gain characteristics at (he lime of reception of 15 vertically polarized waves and FIG. 6C is data indicalivc of the frequency-gain characteristics at the lime of reception of horizontally polarized waves. As illuslratcd in FIG 6A to FIG. 6C, particularly in the band of 570 MI lz to 770 MHz, it was continued that the gain oliaracteristics of about -10 dB or more were obtained both in the vertically polarized waves and in Ihe horizontally polarized waves. In 20 other words, it is known that the reception characteristics arc improved considerably compared lo Ihc gain characteristics (see FIGS. 2A to 2C) in the onboard antenna 1 explained as the first embodiment. [0033] Here, the example is given in which the width of the antenna element 10a is 25 set to the same width from the end lo the end of the ground conductor 23, but this is not limited. The width may be made wider than this and if widened, currents at various frequencies flow through the antenna element 10a, and therefore, it is possible to further improve (he reception characteristics particularly on the high frequency side. 30 [0039] [2-2- Modified example 2] SP342942WO00 14/28 FIG 7 is a schematic diagram illustrating a configuration example of a modified example 2 of the first embodiment of the present disclosure. In FIG, 7, the same symbols arc attached to (he portions corresponding to those in FIG 1 and FIG, 6 and duplicated explanation is omitted. An onboard antenna IB illustrated in FIG 5 7 differs from the onboard antenna 1A illustrated in FIG. 6 in that the ground conductor 23 on the substrate 21 is extended and a second ground element 30a different from the ground clement 30 is provided. [0040] The second ground element 30a is disposed in parallel to an antenna 10 element 10b and separate from the antenna element 30a by a predetermined interval, and the length in the longitudinal direction thereof is made shorter than the length of the antenna clement 10b. With this configuration, a J-type antenna is configured by the antenna element 10a and the second ground clement 30a. [0041] 15 By adjusting the length of the second ground element 30a and the distance from the antenna clement 10a, an image current at the frequency received by the antenna element 10a begins to flow through the second ground clement 30a. Consequently, it is made possible to take out the sum of the signal of tiic desired wave and the image current as a received signal at the feeding point Fp, and therefore, 20 it is possible to increase the level of the received signal. In other words, it is possible to improve the reception sensitivity of the antenna. As specific dimensions, for example, in the case where a signal in the UHF band is received, the length and width of the antenna element !0a are set to 130 mm and 8 mm respectively, and the length and width of the second ground element 30a are set to 85 mm and 3 mm 25 respectively. Then, the interval between the antenna element 10a and the second ground clement 30a is set so that signals received by the antenna clement 10a and the second ground element 30a respectively can be isolated from each other. [0042] FIGS. 8A to SC are a graph and tables showing the frequency-gain 30 characteristics when the onboard antenna "IB of the present embodiment receives a broadcast in the UMF band. The length of the ground element 30 is set to 100 mm SP342y42WO00 15/2B and the length of the coaxial wire 40 is set to 1.5 in. FIG BAis a graph and FIG 8JJ and FIG SC illustrate data. The horizontal axis in FIG 8A represents the frequency (MHz) and the vertical axis represents the peak gain (dBd). The solid line in the graph represents the gain characteristics at the time of reception of horizontally 5 polarized waves and the broken line represents the gain characteristics at the time of reception of vertically polarised waves. FIG BE is dala indicative of the frequencygain characteristics at the time of reception of vertically polarized waves and FIG 8C is data indicative of the frequency-gain characteristics at the time of reception of horizontal [y polarized waves. As illustrated in FIG, SA to FIG, 8C, in the portion of ]0 high frequencies particularly around 670 MHz to 750 MHz, it was confirmed that Ihe gain characteristics of-8 dB or more were obtained both in the vertically polarized waves and In the horizontally polarized waves. Particularly in the horizontally polarized waves, the favorable characteristics of-5 dl3 or more are obtained. In other words, it is known that the reception characteristics are improved considerably IS compared to the gain characteristics in Ihe onboard antenna of each embodiment described above. 10043J For the onboard antenna 1H of the present embodiment, a field test to evaluate the running characteristics was also conducted. The field lesl was 20 conducted by attaching both Ihc conventional film antenna and Ihe onboard antenna IS of the present embodiment to one vehicle and by running through areas where the electric field was weak and areas behind buildings where radio waves were weak and affected by fading. Then, by watching and listening to the videos of the predetermined broadcast wave received by the two antennas, respectively, how the 25 block noise appeared in the video was clicckcd. In other words, the lengths of intervals at which block noise was generated, the way the generated block noise . appeared, etc,, were compared, 'Ihe east end of the area where the filed test was conducted is around Tshikawadai, Ohta-ku, Tokyo about 10 km apart from (he Tokyo tower from which the broadcast wave arc transmitted, and the west end is around the 30 Musashishinjo, Nakahara-ku, Kawasaki-shi, about 5 km apait from the east end.in the south-west direction. The north end is around Todoroki, Setagaya-ku, and Ihe 3P342942WO00 16/28 south end is around Shinmaruko, Nakahara-ku, Kawasaki-shi. [0044J As the film antenna, two antennas were provided in order to perform diversity reception and the antennas were bonded to the upper-right portion and to 5 the upper-left portion of the windshield, respectively. On the other hand, similarly the two onboard antennas IB (see FIG 7} were pnivided and arranged in the right end portion and in the left end portion on (he dashboard, respectively, and each ground element 30 was caused to extend along the left and right pillars of the vehicle . body. The reception channel was TOKYO MX (physical channel: UHF band 20ch, 10 center frequency: 515 MHz, transmission output: 3 kW). The wcatlicr of the day when the field (est was conducted was fine. [00451 As the results of the field lest, the way the block noise appeared in the video was substantially the same by (he film antenna and by the onboard antenna IB of Use IG present disclosure in the residential streets around the Shinmaruko, Musashinakahaia, and Musashishinjo. In contrast to this, in the section from the Tamagawu fC to (he Keihin Kawasaki. IC of the Haisan Keihin highway, in the area from Ishikawadai of Nationat Route 312 to the Tamagawa IC, and in the aitsa from Ishikawadai of National Route 311 lo Shinmaruko, less block noise appeared by the onboard 20 antcmia 111 of the present disclosure. In other words, (he reception characteristics more excellent than those of the film antenna were confirmed. Also in (he case where the onboard antenna IB of (he present disclosure, was disposed 10 cm apart from the pillar, it was possible to obtain substantially the same reception characteristics. 25 10046] In other words, accoixiing lo the present embodiment, the effect equivalent lo that of the onboard antenna according to each embodiment described above is obtained and further, the reception characteristics of the antenna arc further improved, [0047] SO In the configuration illustrated in FIG. 7, the example is given in which the antenna element 10a is disposed on the side of the coaxial wire 40 and the second SP3429+2WO00 17/28 ground element 30a is disposed tkcrcabove, but this is not limilcd and an arrangement opposite thereto may be accepted. In other words, the second ground element 30a may be disposed on the side or the coaxial wire 40 and the antenna clement 10a may be disposed thercabovc. 5 [0048] [2-3. Modified example 3] Next, a configuration example of an onboard antenna 1C according lo a modified example 3 of the present embodiment is explained with reference lo FIG 9. In 1'Ki 9, ihe same symbols arc attached to the portions corresponding to those in 10 FIG 1, FTG 5, and FIG 7 and duplicated explanation is omitted. lite onboard antenna 1C illustrated in FIG. 9 has a configuration in wliich two antenna elements made of a linear metal member are provided and the second ground element 30 is shared by the two antenna elements. An antenna element 10-1 and an antenna element 10-2 are arranged so as to face in different directions so that the correlation 15 of the reception state between the two antennas is as small as possible. [0049] A substrate 21b is pnividcd with two sets of the signal pattern 22 and the ground conductor 23 and (he antenna clement 10-1 and the antenna element 10-2 are connected to (he different signal patterns 22, respectively. Then, on the side of the 20 signal pattern 22 to which no antenna element is attached, a coaxial wire 40-1 for the antenna clement 10-1 and a coaxial wire 40-2 for the antenna element 10-2 are provided separately, [0050] With this configuration, even in the case where two antenna elements are 25 necessary to perform diversity reception, it is only necessary to dispose the onboard antenna 1C on one side on the dashboard {not illustrated). Further, even in (he case where diversity reception is performed using four antenna elements, it is ..only necessary lo dispose the two onboard antennas 1C on both sides on the dashboard, According to the onboard antenna 1C of the present embodiment, it is possible lo SO obtain the effect equivalent lo (he effect obtained in each embodiment described above. SP342942WO00 1S/2S [0051] . In the piesenl embodiment, the example is given in which the antenna dement 10-1 and the antenna clement 10-2 ore configured by Ihc same member (metal member), but mis is not limited. For example, it may also be possible to 5 Ibrm one of the two antenna dements by a substrate and to configure the other by a metal wire material. At this time, by arranging the antenna element configured by a substrate so as to be horizontal with respect to the dashboard and by configuring the other antenna clement by a linear metal member and arranging the antenna element so as to stand vertically, it is possible to reduce the degree of correlation between 10 both the antenna elements. [0052] <3. Second embodiment examp!e> Nest, a configuration example ofan onboard antenna according to a second embodiment of the present disclosure is explained with, reference to FIG 10, TnFTG 15 10, the same symbols arc attached to the portions corresponding to those in FIG 1, FIG 5, FTG. 7, and FIG 9 and duplicated explanation is omitted. In an onboard antenna ID according to the present embodiment, an antenna clement 10b and a ground clement 30b are configured by a rod antenna (rod-shaped antenna), [0053J 20 As the ™d antenna caused to function as the ground element 30b, tor example, a type in which the angle fbnned by the antenna portion and the support portion (relative position) may be adjusted to any angle is used. The antenna clement 10b and the ground element 30b arc connected via the high frequency transmission line (not illustrated) described above etc- and the connection portion is 25 covered by a resin case. In the present embodiment, the connection portion of the ground clement 30b and the substrate of the high frequency transmission line is provided with a.rotary mechanism 31 including a earphone jack of